Temtop P10 Air Quality Monitor PM2.5 AQI Professional Particle Sensor

as far as I can tell it worked. hard to quantify something you cannot see

I like the design and price, but the PM2.5 measurement -µg/m³- is off by approximately 25 µg/m³. The unit measures my indoor air quality at 1-2 µg/m³, which is inaccurate. I don't live in a clean lab. Outdoors, when smoke was here from Canada and the weather apps showed PM2.5 levels at about 75 µg/m³, this device showed about 30. On normal days outside, this device shows PM2.5 at about 10 when the weather service reports about 45. So the device does measure, just inaccurately. In hopes I had one bad unit, I bought a second. Same problem. I think the other measurements are working okay - at least comparable to another device I have by a different maker. Sad the company apparently doesn't implement quality control and allows itself to sell devices important to health that work improperly.